Steering system for a torpedo



STEERING SYSTEM FOR A TORPEDO Filed May 14, 1947 3 Sheets-Sheet 1 PCA o o v o t! u I lNVEN-R WITNESSESZ j Thoma. Daly and ATTORNEY Sept' 11, 1962 T. A. DALY ETAL 3,053,217

STEERING SYSTEM FOR A TORPEDO Filed May 14. 1947 5 Sheets-Sheet 2 wlTNEssEs: 7 lNvENToR/ homos/@D00 an Z ffep/v A/Owa/ys/yyqfr.

ATTORNEY Sept, 11, 1962 T. A. DALY ET AL 3,053,217

STEERING SYSTEM FOR A ToRPEDo Filed May 14, 1947 s sheets-sheet s INVENTORS WlTNs/ss' Thomas ADa/y and Sephen/@wa/yfhy/z. @j l BY ATTORNEY 3,653,217 Patented Sept. 11, 1962 States of America as represented by the Secretary of the Navy Filed May 14, 1947, Ser. No. 748,078 6 Claims. (Cl. 114-24) This invention relates, generally, to electrically operated and controlled conveyances, and, more particularly, to conveyances of the type adpated for operation in a fluid medium.

More in particular, this invention is directed to an all Yelectric torpedo having a novel system of control.

In certain of its aspects, this invention is related to a copending application of T. A. Daly and S. Kowalyshyn, Jr., Serial No. 699,040, filed on September 24, 1946, entitled Electrical Control Systems, now Patent No. 2,948,- 248, and to the copending application of H. L. Prescott and S. Bennon, Serial No. 761,480, filed July 17, 1947, entitled Electrical Control Systems, each application being assigned to the same assignee as this invention.

it has been recognized for some time that torpedoes in which compressed gases are utilized as the energy source, either to drive turbines connected to the propulsion screws or to be exhausted as a jet, are undesirable for war sho-t purposes since the torpedo wake caused by the exhausted gas reveals the approximate location of the submarine from which the torpedo was fired as well as the course of the torpedo. Efforts directed to producing a torpedo leaving no wake have resulted in the development of torpedoes powered by electric motors. This, of course, required the inclusion of a large supply of electric energy suitable for adequately supplying the electric motor for the duration of the torpedos run. Usually the source of energy is of the form of the primary or secondary battery.

With electric power available in the torpedo, the problem of supplying electrical power for equipment providing control of the torpedos movement is minimized. Accordingly, considerable development effort in the accomplishment of this end has been expended.

Initially, controls of this type included depth and directional control devices for the torpedo which maintained a selected course and depth of operation once the torpedo was launched. In one control arrangement, a gyroscope which controlled solenoids actuating directional rudders and a pressure and longitudinal tilt responsive apparatus controlling solenoids actuating depth rudders or elevators were utilized as the movement controlling elements.

Later renements of this equipment permitted launching of the torpedo in any predetermined direction by simple presetting of the gyroscope control, the control being such as to cause the torpedo to traverse a predetermined arc and then head towards the intended target'.

While such electrical control systems for torpedoes offered measurable improvements over prior art schemes, both in respect to accuracy of control function and reliability, the possibility of electrical control oifered yet more desirable performances in the form of a control providing what may be generally termed automatic tracking of the target by the torpedo.

There are, of course, a number of ways in which electric equipment may be utilized to detect and effect track- .ing of a target, but a simple yet eifective scheme includes the use of piezo electric crystal or magnetostriction generators which will produce voltages depending upon the impinging noise level, such noise or vibration level being caused, for example, by the propulsion screws and/or machinery noises of conveyances operating in the fluid medium. By properly utilizing the crystal or magnetostriction hydrophones as the control elements in control systems affording control, for example, of a torpedo 1n horizontal and vertical control planes, the torpedo can be made to follow a path tending always t0 terminate at the vibration or signal source constituting the target.

As in the case of the two above-mentioned copending applications, this invention provides a control of the torpedo wherein, during a preset interval of time, the torpedo is controlled directionally by means of a gyroscope and its depth is regulated at a preset level, say of the order of feet, by means of a hydrostat and a pendulum, the two controls operating respectively the steering and depth rudders.

After the expiration of the said interval of time, surtable controls are initiated to provide for switching over of the steering and depth control of the torpedo to the acoustic control, the switch over of the control depending in general upon the magnitude and duration of the signal being picked up by the acoustic system. In this fundamental aspect of the control, the present invention is similar to the above-mentioned copending applications. However, as will hereinafter become appartent, this invention provides a more etfective switch-over control effected by a different method.

One object of this invention is to provide a highly effective and ecient torpedo.

Another object of this invention is to provide a torpedo which will automatically track a target.

Another object of this invention is to provide a torpedo which is as simple as operational requirements will permit.

Yet another object of this invention is to provide a torpedo characterized by the feature of automatic tracking of a target, as hereinbefore generally described, in which provision is had largely through mechanical and electrical symmetry in torpedo design for minimizing the tendency of the torpedo to respond to the vibrations of its propulsion screw or screws.

Still another object of this invention is to provide a, torpedo of the character referred to which is initially operated for a timed interval according to a predetermined control pattern providing a predetermined direction of movement and depth of operation thereof, which,

at the end of said timed interval, is set for automaticr tracking of a target but which yet is controlled according to the original control pattern in the event the target signal` is yet too weak because of target remoteness or, other reason, to provide adequate automatic tracking control.

A specific object of this invention is to provide a torpedo having an acoustic gear containing horizontal and vertical acoustic channels, and having a gyroscope and depth mechanism for initially controlling the torpedo according to a preset control pattern in which means are provided for switching the control of the torpedo from the gyroscope and depth mechanism to the acoustic gear depending upon the electrical output of the vertical acou- Stic channel.

Another specific object of this invention is to provide a torpedo of the character mentioned which is initially operated for a timed interval acocrding to a predetermined control pattern affording the desired depth of operation and direction of movement thereof, which at the end of said timed interval is acoustically enabled but which yet proceeds according to the original control pattern should the acoustic [field lack the proper intensity level, or should the torpedo be headed directly for the target, but which, under such condition, functions in conjunction with a portion of the acoustic gear under the influence of gyroscope control to maintain the original control pattern and which, upon the occurrence of an acoustic signal of proper magnitude and duration, im-

mediately proceeds to track the target under the iniiuence of the control afforded by the acoustic gear.

The use of the acoustic gear in tracking of a target while affording measurable improvements in accuracy of performance has presented several problems requiring special safeguards to protect the launching craft as well as friendly craft in the immediate vicinity or between the target ship and launching craft. These conditions exist because of the tendency of the torpedo once it is enabled for acoustic tracking, to select for tracking the strongest signal sensed by the acoustic gear. Thus an acoustically enabled torpedo at launching, if the launching craft were proceeding under its own power, may pick up the signal thereof and commence tracking. Similarly, a signal of a friendly craft in the path of operation of the torpedo may result in the torpedos tracking thereof.

For this reason, it is essential that means be provided to obviate acoustic enabling of the torpedo at launching, and which means at the same time is sufficiently fiexible in operation to afford variable settings of range and/or time for operation of the torpedo by the gyroscope and depth control exclusively of the acoustic control that the torpedo may strike beneath and beyond the acoustic fields of friendly `craft at the intended target prior to acoustic enabling.

The foregoing control functions require consideration of the effective acoustic range or field of the torpedo. Hence, to the known range of a friendly craft must be added an additional distance or range sufficient to clear the torpedo of the effective sound field of the friendly craft.

Accordingly, it is another object of this invention to provide in a system of control for a torpedo having an acoustic tracking gear, a suitable means for preventing the torpedo from tracking the launching craft.

Yet another object of this invention is to provide a torpedo of the character referred to in which provision is had for clearing the torpedo of the effective sound field of friendly ycraft prior to acoustic enabling of the torpedo.

Still another object of this invention is to provide a torpedo of the character mentioned in which provision is had for varying the distance from the launching craft at which the torpedo may be acoustically enabled after the torpedo is installed in the launching tube.

In the use of torpedoes against various types of vessels, it has been found desirable to provide more than a single speed of operation. ln general, the acoustic type of torpedo, herein disclosed, ydisplays less tendency to track its own signal when it is operated at low speeds and its own noise level is low. Such a speed of operation of course is not desirable against fast moving ships since the torpedo speed would be too low to overtake the ship being tracked. However, against slower moving craft such as freighters, the slow speed of operation has been found adequate. Additionally, by proper use of the batteries in the torpedo it is possible to increase the effective range thereof and the torpedo may therefore -be launched from greater distances, and the launching submarine or vessel is less liable to -be detected.

It is, therefore, a further object of this invention to provide a system of batteries for supplying electric energy to the propulsion motors of the torpedo in which means is had for connecting the batteries either in series or in parallel circuit relation to provide two predetermined speeds of operation of the torpedo.

The foregoing statements are merely illustrative of the various aims and objects of this invention. Other objects and advantages will become apparent upon a study of the following specification when considered in conjunction with the accompanying drawings, in which:

FIGURE l is a block diagram illustrating the elemen- 'tary features of this invention;

FIG. 2 is a diagrammatic showing of a torpedo control system for test purposes embodying the principles of this invention:

FIG. 3 is a variation of the invention of FIG. 2 affording a control scheme whereby torpedo control for warshot purposes is had, and

FIG. 3a is a schematic showing of an arming circuit employed in conjunction with the circuit of FIG. 3.

With the torpedo of this invention, the torpedo may be fired at points from the target approaching the torpedos maximum range and set to follow a course having any desired angular relation wtih the path of the launching craft within preset limits which will hereinafter be defined. Thus the torpedo may be red from safe ranges and caused to pursue a path directed towards the target, and, when an acoustic signal of the target of sufficient magnitude is received, the torpedo is automatically directed along a path tending always to terminate at the target.

The elementary diagram of FIG. 1 illustrates the control arrangement, generally, Whereby the foregoing desirable control functions are accomplished. The control provides two distinct types of directional and depth control for the torpedo. The first is the type which directs the torpedo along a predetermined course at a predetermined depth, and this control is initiated by the gyro'scope steering mechanism generally designated G and by the depth control unit designated DC. The second type of control involves the acoustic gear which is arranged to respond to vibrations of the fluid medium in horizontal and vertical planes. The horizontal acoustic channel H includes the starboard and port hydrophones SH and PH, respectively. These hydrophones are connected with a discriminator D, which in turn is connected with an alternating current amplifier which amplifies the output of the discriminator. The output of the amplifier ACA is supplied to a detector and filter circuit, designated DF, which in turn controls the direct current amplifier DCA. Direct current amplifier DCA controls a relay 3K and the relay 3K through suitable control relays, designated CR, operates the port and starboard solenoids, designated PSS, to obtain steering in the proper direction.

In the vertical channel V of the acoustic gear, a single set of hydrophones, designated UH and LH for upper hydrophone and lower hydrophone, respectively, are provided to control the output of the vertical channel. Like the horizontal channel, the vertical channel also includes the discriminator D, the A C. amplifier, ACA, the detector and filter circuit DF, a D.C. amplifier, DCA, and a relay 4K which is controlled by the output of the direct current amplifier of the Vertical acoustic channel. Relay 4K through certain of the control relays of the control relay unit CR and in conjunction with the depth control DC operates the up and down solenoids UDS after enabling to control the depth of operation of the torpedo.

The discriminators and the detector and filter circuits of both the horizontal and vertical acoustic channels are controlled by an oscillator O. This oscillator is so arranged that its signal synchronizes the operation of the discriminator and the detector and filter which are associated in the respective channels so that signals from the associated pair of hydrophones are alternately applied from the discriminator through the A.C. amplifier into the detector and filter circuit, where the signals are compared as to magnitude and their differential applied to the grid circuits of the D.C. amplifier.

More in particular, the discriminator in each channel is equipped with a pair of tubes which are connected in parallel. These tubes are provided with a predetermined bias upon their grid circuits. The oscillator signal is so connected with each of the `grids of the parallel connected tubes that its signal first sweeps the grid of one of the parallel tubes over its conducting range and then on the other half cycle of the oscillator its signal sweeps the grid of the other of the parallel connected tubes over its conducting range.

The hydrophones each form a part of resonant circuits which are respectively connected with the grids of the parallel connected tubes. The frequency of these resonant circuits is well above that of the oscillator signal and the output circuit of the parallel connected tubes contains a resonant circuit which is tuned to the same frequency. Thus during periods when there is no hydrophone signal on the grids of the parallel connected tubes of the discriminator, the oscillator sweep voltage causes no output of the discriminator tubes. However, upon the occurrence of a signal from the two hydrophones on the grids of the discriminator tubes, the output circuit of the tubes which is tuned to the resonant frequency of the hydrophone circuits passes the alternate spurts of energy from the discriminator tubes as controlled by the oscillator sweep voltage or signal. The input circuit of the A.C. amplifier is tuned to the resonant frequency of the hydrophone signal and, as a consequence, this signal is passed through and amplified in the A.C. amplifier to the detector and filter circuit.

The detector and filter circuit DF includes a pair of diodes, and the cathodes of these diodes are relatively positive with respect to the plates thereof. As a consequence, these diodes will not conduct until the cathode biases are overcome. As previously mentioned the oscillator signal is applied to the detector and filter circuit in a manner to synchronize its function with that of the discriminator. In accomplishing this, the oscillator signal or sweep voltage is so applied to the diodes of the detector and filter circuit that the diode associated with one of the parallel connected tubes of the discriminator circuit has applied thereto a voltage just slightly smaller than the voltage required for this tube to become conducting and this voltage is applied at the same instant as the corresponding tube in the discriminator circuit is enabled by the oscillator and passing the associated hydrophone signal. During the next half-cycle, the other diode is synchronized to be enabled by the oscillator sweep voltage with the enabling of the other tube of the discriminator circuit. Thus in effect, the oscillator switches the A.C. amplifier back and forth between the corresponding tubes of the discriminator and the detector and filter so that the spurts of hydrophone signal passing through the system` are amplified by the diodes functioning as detectors in the system and passed to the filter or differential network. The signals are compared in the differential network and, as Ipreviously explained, the differential signal is applied to the direct current amplifier which through the relay 3K controls the port and the starboard solenoids. While this description has been confined to the horizontal channel, it will be understood that the vertical channel functions in a similar manner and further description thereof is believed unnecessary.

The foregoing description concerning the acoustic gear has been of a general nature, further details thereof will be disclosed and described in connection with the detailed description concerning FIG. 2. This functional description is presented at this time so that the details which follow may be more readily appreciated and understood. It should be noted at this time that the acoustic gear, per se, forms no part of this invention.

In the operation of the torpedo for exercise shots or test purposes, means are provided for recovering the torpedo at the end of the trial run. Stop circuits for accomplishing this are initiated through the timers of the single block designated 1T and 2T. In the actual embodiment, the timer 1T is utilized in the test torpedo to initiate, at the time of launching of the torpedo, control circuits through normally closed contacts and, after the time interval set by the timer has elapsed, these circuits are interrupted to `deenergize .the torpedos propulsion and control systems in conjunction with the function of the control relays. Additionally, circuits are initiated through the closure of normally opened contacts of the timer 1T to initiate operation of the ballast control designated BB through the control relays. At the same time, through the control relays the locator oscillator LO is set into operation. This oscillator excites a small diaphragm I(not shown) in the hull of the torpedo to cause vibration thereof in the fluid medium, producing a signal which may be located with suitable direction finding equipment facilitating in the location and recovery of the torpedo.

The ballast control of the torpedo exhausts the liquid ballast which is Provided for the purpose of making the torpedo negatively buoyant to simulate the war shot torpedo. When the liquid ballast is exhausted, the torpedo is brought to the surface where it may be easily recovered and towed back to the starting point in preparation for additional tests and inspection.

The timer 2T forming a part of the control system is utilized to control the enabling distance of the torpedo. This timer may be varied over any range setting up to the maximum range of the torpedo and functions through the control relays to provide acoustic enabling of the torpedo at the selected range.

The foregoing discussion covers the control of the torpedo afforded by the acoustic gear in both the horizontal and vertical control planes and the gyro control devices in the horizontal plane and depth control in the vertical control plane. The operating sequence of these two con- `trols is established by the timer 2T, which through the medium of the control relays to be hereinafter described in detail connects the gyro G along with its companion depth control DC to the respective groups of rudder solenoids. After a certain timed interval determined by the setting of the timer 2T, circuits are established by this timer to enable transfer of the control to the acoustic gear, but only if the acoustic signals are sufficiently strong to properly control the torpedo. Should the strength of the acoustic signals be of insufficient magnitude or of insufficient duration to effect complete transfer to the acoustic system, the torpedo will proceed according to the predetermined control pattern but, in this instance, in the horizontal control plane the gyroscope instead of working directly through the control relays to the port and starboard solenoids of the directional rudders now applies a control to the detector-filter circuit to cause the operation of the relay 3K in response to the gyroscope steering control. The relay 3K operating through the control relays now controls the port and starboard solenoids. This biasing control on the detector and filter circuit does not unblock the two diode tubes of the .detector circuit, but the control, as will be hereinafter explained, is effectively applied to the differential network thereof previously mentioned and results in an unbalance thereof in a .direction depending upon the point in the differential circuit to which the bias is applied. The D.C. amplifier, which is responsive to the output of the differential network thereof is directly affected by the biasing potentials of the gyroscope and the amplifier responds accordingly.

While the torpedo is operating under the infiuence of the biasing control afforded by the gyroscope, should a sound field be encountered, the intensity of the sound field must be sufficient to overcome the effect of the bias on the differential network which is applied by the gyroscope. When this effect is overcome, the torpedo immediately follows the course indicated by the acoustic gear. This course tends to take the torpedo towards the signal source. As the longitudinal axis of the torpedo points towards the signal source, the signal differential of the starboard and port hydrophones drops to a level below that of the biasing effect of the gyroscope on the differential network and, as a consequence, the torpedo is controlled by the gyroscope. This function continues until the signal differential in the vertical channel between the upper and lower hydrophones reaches a predetermined level which is higher than that required to acoustically steer the torpedo in the horizontal plane. When the differential signal of the vertical acoustic channel is of sufficient magnitude for a sufcient interval of time, the relay 4K, in response thereto, initiates circuits through the control relays providing a complete switch over to acoustic control. In the horizontal channel, the relay 3K now operates, to the exclusion of the gyro steering mechanism G, to control the port and starboard solenoid. In the vertical channel, the relay 4K, in response ot the vertical acoustic signal, alternately energizes and deenergizes the depth control DC. In its deenergized condition, the depth control DC applies up rudder to the torpedo tending to cause the torpedo to come to the surface. In its energized position, the depth control tends to keep the torpedo at the depth for which it was originally set. In this capacity, when the vertical channel signal is sufficiently strong the relay 4K functions to deenergize the depth control. Thus the torpedo tends to rise to attack the target.

The discussion hereinbefore presented has been made primarily to set forth the requirements and considerations involved in the design and operation of torpedoes, and to set forth in a general way the manner in which this problem is solved by this invention. Further, while the discussion has `been directed to the entire control scheme, it has been the intention, in part, to cover the acoustic control portion thereof in sufficient functional detail that other elements of the control may be treated specifically and their place in the system readily understood from the previous comments concerning FIG. l. No attempt has been made to detail elements of the discriminator, the A.-C. amplifier, or the oscillator. Since it is felt that the design of such elements which may be conventional is well within the scope of one skilled in the art, and only such details concerning the detector and filter system, together with the direct current amplifier, for each channel, are hereinafter presented as are believed necessary for a complete understanding of this invention.

In the detail showing of this invention in FIG. 2, the components of the detector and filter circuit together with the direct current amplifier for both the horizontal and vertical acoustic channels have been shown. Each of the detector circuits comprises a conventional bridge circuit. In the horizontal channel, the bridge circuit includes a potentiometer P3 and resistors R44B and R44A. The two diode tubes VSA and VSB, which function as detectors in the circuit, are disposed in circuit branches on opposite sides of the bridge circuit. A biasing battery, which may be termed the horizontal bias battery and which is designated HB, is connected through the contacts 5K1 of the relay SK across the input terminals A13 and A14 of the bridge circuit, the positive terminal of the horizontal, bias battery being connected to the terminal A14 and the negative terminal of this battery being connected to A13. A tap on the potentiometer P3i is connected to the terminal B which is grounded through the resistor R63 and the contacts FZ of the filament relay F. With this arrangement, the bridge circuit may be adjusted for balance by movement of the tap along the potentiometer P3 and in effect with the circuit connections illustrated with the bridge yin balanced condition a center point of the horizontal bias battery HB will be effectively at ground potential. Thus the positive side of the horizontal bias battery HB vtu'll be approximately half of the battery voltage above ground, while the negative side of this battery will be approximately half of the battery voltage below ground. In this manner, a positive bias is applied through windings of the transformers T1 and T3 to the cathode of the diode VSA while a negative bias through other windings of T1 and T3 is applied to the plate of the diode VSB. For a balanced condition of the bridge circuit, these biases are of substantially the same magnitude, and hence the two diode tubes are biased to cut off by equal amounts. The resistors R91 and R92, which parallel the potentiometer fil S P3, are inserted primarily for the purpose of controlling the sensitivity of the potentiometer.

The bridge circuit also forms part of a differential network associated with the diode tubes VSA and VSB. The plate of the tube VSA is connected through a resistor R39 to a resistance capacitance network including the condensers CSA and CSB, and the resistor R40, while the cathode of the tube VSB is connected'through a resistor R41 to a similar network including capacitors C6A and C6B together with a resistor R42'. Both of these networks through the terminals H7, H6 and H9 connect with a resistor R43 in such a manner that the tube voltages and the charges on the associated capacitors produced by the electrical output of the tubes are in opposition across the resistor R43. The starboard signal and the port signal are applied respectively to the tubes VSA and VSB through the windings of a transformer T1 while the oscillator signal or sweep voltage is applied to both of the tubes through windings of the transformer T3.

The direct current amplifier DCA comprises the two tubes V6 and V7. The tube V6 has its grid connected to the terminal H7 of the differential network. Hence the grid voltage of the tube V6 depends upon the differential of the voltages produced by the tubes VSA and VSB across the resistor R43, and the tube V6 is either conducting or non-conducting depending upon the magnitudes of the starboard and the port signals. Tube V7 is controlled in dependence of the plate voltage of the tube V6 and to this end has its grid connected with the plate circuit of the tube V6. The plate voltages for both of the tubes V6 and V7 are obtained from a battery 6 which is connected in series with a battery S, the negative side of which is grounded through the contacts F2 of the filament relay. This plate voltage is applied to the system through contacts 5K3 of the relay 5K and to the plate of the tube V6 through a resistor R48, while that for the plate of the tube V7 is applied through the coil of the relay 3K. The cathode circuits of the tubes V6 and V7 are connected to the positive side of the battery S through the contacts 5K2 of the relay SK. This circuit includes resistors RSZA and RSZB and terminates at ground. A small voltage is applied to the cathode of the tube V6 by means of the resistor RSZA while the cathode of the tube V7 has applied thereto the output voltage of the battery S. The circuit arrangement is such that when the tube V6 is conducting due to the control of its grid by the differential network the plate current flow thereof results in a drop in plate voltage. This drop in plate voltage biases the grid of the tube V7 more negatively and, as a consequence, V7 is cut off. Under these conditions, there `is no plate current flow in V7 and the relay 3K, which after enabling and during operation of the acoustic gear, controls the steering rudder remains deenergized. Conversely if the control of the grid of tube V6 by the differential network biases the tube V6 more negatively, the tube V6 passes less current and, as a consequence, its plate voltage rises. This rise in plate voltage causes the grid of V7 to become more positive and V7 passes current. With the occurrence of plate current flow in the tube V7, relay 3K is energized to initiate a reverse control on the steering rudders.

Under conditions in which the bridge circuit is balanced and the detector circuit is not influenced by the oscillator signal voltage or port and starboard signals, it will be apparent that the terminal H7 of the differential network will be substantially at ground potential.

The bridge circuit of the detector and filter circuit in the vertical channel, including the resistors R94 and R93 in adjacent legs and the resistors R47B and RLY/A in the remaining two adjacent legs, is controlled by the potentiometer P4. Unlike the bridge circuit of the horizontal channel, this circuit is unbalanced a predetermined amount by adjustment of the potentiometer P4. This adjustment is `such that in the absence of an oscillator signal on the transformer T4 and the absence of an up or `down `signal on the transformer T2, a predetermined negative bias from the terminal U17 of the differential network is applied to the grid of the tube V14. As a consequence, the tube V15 is conducting and the plate current ow of this tube energizes the relay 4K which operates through the depth control DC to control the up and down solenoids US and DS. As a consequence, a predetermined diiferential in magnitude of the up and down signals must exist, that is, the up signal must predominate by a predetermined amount to overcome this bias. 'Ihe various details of the detector and filter circuit, as well as the direct current amplifier of the vertical channel, are similar to those of the horizontal channel. Terminal B10, which it will be noted is connected to a tap of potentiometer P3 in the horizontal channel, is similarly disposed at terminal B16 in the vertical channel between the resistors R94` and R93. The vertical bias battery VB has its positive terminal connected through contacts 5K4 of relay 5K to terminal A16 of the bridge circuit and the negative terminal of the bias battery is connected to the terminal of the bias battery is connected to the terminal A of the bridge circuit. Thus in a manner similar to that in the horizontal channel detector and lter circuit, the tubes V13A and V13B are provided with cutoff biases. The plate circuit of the tube V13A is connected through a resistor R59 to the network including the capacitors C14A, C14B and resistor R6@ while the cathode of the tube V13B is connected through the resistor R61 to the network including capacitors CISA, C1513 and the resistor R62. Terminals U17, U16 and U19 complete the connections of the differential network which includes the resistor R58 connected between terminal y of the bridge circuit and the terminal U16. In the direct current amplifier of the vertical channel, the resistors R21A and R213 provided the necessary cathode biases for the tubes V14 and V16. The principle here is rsimilar to that embodied in the circuit connections of the cathodes of the tubes V6 and V7 of the horizontal channel. Plate supply for the tube V14- is `obtained from a parallel branch of the circuit of battery 6 and it is applied to a resistor R49. The plate supply of the tube V15 is applied from the battery 6 through the coil of the relay 4K.

Referring now to the horizontal channel, the function of this portion of the network may be as follows: After passing through the AiC. amplifier, the alternate spurts of signals from the port and starboard hydrophones are impressed respectively on the diodes VSB and VSA of the detector circuit through the medium of the transformer T1. As previously noted, these diodes are connected to the horizontal bias battery through the output windings of the oscillator transformer T3 and signal transformer T1 in such a way that the plate of each diode is biased negatively with respect to its cathode. The oscillator signal voltage is so adjusted that its peaks are slightly less than the bias voltages so that when no hydrophone signal is present the diodes are non-conducting. When the signal superimposed on the oscillator peak voltage is suciently strong, the biases are overcome and rectified currents flow into the output networks of the diodes. Thus the function of the oscillator and the superimposed signal voltage is to enable one of the diodes and then the other in synchronism with the similar alternate enabling of the input tubes in the discriminator circuit. In effect it is as though there are separate input and detector circuits for each hydrophone but only one A.C. amplifier which is switched to join one set of circuits and then the other.

Assume rst that there is no oscillator signal and no hydrophone signal applied to the transformers. Since the bridge is in balanced condition, there is no difference in potential between the terminals x and y. Thus there is no difference in potential between the grid of the tube V6 and ground due to the bias battery. If, however, the po- 'cycle of the oscillator signal.

tentiometer is moved off center, a potential difference exists between the grid of tube V6 and ground. A movement of the potentiometer towards the positive side of the battery, that is, a movement of x towards terminal B13 causes the terminal A1, which is essentially ground, to become positive with respect to y, and therefore the grid of the tube V6 becomes more negative withv respect to ground. Conversely, a movement of x towards the terminal B17 causes the grid to become more positive with respect to ground. This principle is utilized in the biasing control afforded by the gyroscope as will hereinafter become apparent.

Assume now that there is power in both the oscillator signal and the hydrophone signal transformers T3 and T1, respectively. During the half-cycle that a diode is conducting, rectified signal power flows, for example, into the upper portion of the differential network from the tube VSA and charges the condensers CSA and CSB. The charge dissipates itself at a relatively slow rate through the resistor R43 which is of relatively high ohmic value as compared with the other resistors of the network. This provides a time constant and gives a period of discharge that is long compared with the time per Thus the spurts of signal energy rectied by the diode maintain a fairly constant direct current potential across the resistor R43.

While this direct current potential across resistor R43 is being caused by the diode VSA, a -direct current potential in the opposite direction is being caused similarly by the other diode VSB. The 'resultant potential, either positive or negative in net value depending upon which diode receives the stronger signal, is impressed upon the grid of the tube V6 of the direct current amplier and causes the relay 3K to respond accordingly giving port or starboard rudder depending upon which of the port or starboard signals predominate.

`Consider the case when the starboard signal is stronger than the port signal. The rectified signal current through the starboard diode VSA flowing in the direction of plateto-cathode charges the condensers CSA and CSB of the differential network in such a manner that current flow in the resistor R43 is in the direction of yy to H6. This `biases the grid of the tube V6 more negatively with respect to ground. In a similar manner, the rectified signal current through the port diode VSB produces a bias on the grid of the tube V6 in a positive direction but the net bias caused by the signal is negative since the starboard signal is assumed to predominate.

Because of this negative bias, the plate current in the tube V6 decreases and the plate-potential of V6 increases. This raises the grid potential of the tube V7 and carries this tube above its cutoff point causing current flow in the plate circuit thereof which includes the winding of the relay 3K. The control thus afforded by the relay 3K is such `as to apply power to the starboard solenoid so that the rudders deflect towards the starboard and steering in lthat direction results.

The function of the detector and filter circuit and the direct current amplifier of the vertical channel will be understood in connection with the description just given lfor the horizontal channel since the elements of the vertical channel are essentially a duplicate of those of the horizontal channel.

The various control circuit elements which function in conjunction with the acoustic gear to control the operation of the exercise shot torpedoare detailed in the lower portion of FIG. 2. This circuit system includes:

(1) A secondary battery system to provide energy for the control circuits. This battery is comprised of two sections designated 1 and 2, respectively. Section 2 of the battery is utilized in addition to furnishing power along with the battery 1 to the propulsion motors M1 and M2, to furnish power to the control relays and other components of the control system. The circuit arrangement connecting these batteries includes the control switch l l CS which connects the batteries either in series or in parallel with the propulsion motor circuit.

(2) Steering is obtained through the medium of a contact making free running gyroscope which is impulse started by detonating a powder charge. Detonation in this instance is afforded by means of an electrical detonating cap, designated GC, and the products of combustion of the starting cartridge are utilized Ito accelerate the rotor of the gyroscope to operating speed. The gyroscope operates the port and starboard solenoids before enabling and after enabling if the differential of the horizontal signals is too small.

(3) A depth control unit DC embodying a phase advance control for the depth rudder maintains the torpedo at a predetermined operating depth.

(4) A timer and variable enabler, respectively, designated 2T and VEN, are driven during a -torpedo run through a centrifugal clutch CC off the propulsion motors and prevent acoustic control until the torpedo has traveled a suicient distance from the sound field of the launching craft or the sound field of a friendly craft to prevent unwanted automatic tracking. The Variable enabler, as will hereinafter lbe apparent, permits a continually Variable setting of the enabling distance prior to ring of the torpedo from the launching tube.

(5) A depth cutout DCO, which may be a hydrostat, is utilized in the control system to stop the torpedo and exhaust the liquid ballast should the torpedo go below a predetermined safe operating depth. In this connection, a carbon dioxide flask, `designated CO2, is utilized to exhaust the liquid ballast from the torpedo. A broach cutout, designated BCO, functions in an opposite sense to stop the torpedos run should the torpedo corne to the surface.

(6) An anti-circling run circuit, designated ACR, functions in conjunction with the timer 2T of the variable enabler to prevent the torpedo from circling back and striking the launching craft should premature enabling occur. This circuit operates in conjunction with the relay E which deenergizes the auxiliary star-t relay AS to remove power from the control relays thereby deenergizing the motor switch MS and stopping the propulsion motors. In the war shot torpedo, stopping of the forward motion causes the torpedo to sink because of its negative buoyancy.

(7) A timer 1T is utilized in the exercise shot torpedo to control the operating sequence of the torpedo controls, in part, and to determine the length of the torpedos run. This timer is interlocked with the stop relay ST which controls, in part, the application of electrical energy to the tiring cap of the carbon dioxide flask as well as the motor switch MS.

(8) The switch over control from gyroscope steering and depth control to the acoustic gear is obtained in a control system including the control tube 2CT' which is of the gas-filled type. Breakdown of this tube is controlled by the vertical acoustic channel through the relay 4K controlling the auxiliary gate relay AG which has immediate control of the tube ZCT.

(9) Enabling of the torpedo for acoustic control is initiated by the relay EN which in turn is controlled by the auxiliary enabling relay AEN. Relay AEN is energized `depending upon the setting of the distance switch 2T1 of the variable enabler timer ZT. Thus an accurate control of the time or distance, when enabling is had, is obtained.

As illustrated in the drawings, the propulsion motor system of the torpedo includes the two motors Ml and M2. Physically this arrangement involves a pair of armatures disposed within a single frame in tandem relationship. These armatures react with the field produced by the stator windings (not shown) in such a manner that they rotate in opposite directions. The armature or rotor of forward motor M1 is disposed upon a shaft which extends through the armature of the motor M2 and is connected with the aft propeller of the torpedo (not shown). The armature of motor M2 engages a hollow shaft concentrically of the shaft of M1 and this hollow shaft engages the forward propeller (not shown) of the twin screw drive of the torpedo. By properly matching the torpedo propellers, which rotate in opposite directions as a result of these connections, the propeller torques may be balanced to obviate any measurable turning moment about the longitudinal axis of the torpedo which would interfere with the `directional control.

As previously noted in the general discussion in the opening pages of this disclosure, it is desirable that the torpedo have two speeds of operation. The connections afforded by the controller switch CS, disposed bet-Ween the batteries l and 2 and the propulsion motors M1 and M2, provides either a series or parallel connection of the batteries l and 2 with the propulsion motors, the parallel connection providing the low operating speed and the series connection providing the higher operating speed. Rotation of the control switch CS clockwise to bridge the switch terminals 2- and ll-lconnects the batteries 1 and 2 in series with the propulsion motors. This circuit may be traced from the positive terminal of battery 1 to the terminal 1+ of the control switch, thence to the terminal 2- of the control switch to the negative terminal of battery 2. The circuit continues through the motor switch contacts MSIito the propulsion motors and returns to the negative side of battery 1. The parallel connection of batteries 1 and 2 with the propulsion motors is obtained by counterclockwise rotation of the control switch so that its contacts bridge the control switch terminals 1+ and 2+. With this connection, the positive terminals of both batteries 1 and 2 are connected through the motor switch contacts MST to one side of the propulsion motor while the negative terminals of both batteries are connected through the terminal 1- of the control switch and its adjacent terminal 2 to the Opposite side of the propulsion motors.

It will be observed that irrespective of the series or parallel connection of the batteries to the propulsion motors that the battery 2 alone supplies power to the various other elements of the control system. It will also be understood that a difference across the battery 2 will exist when connected in series or in parallel due to the different current drain for the series and parallel connections. The voltage of battery 2 being smaller when in series ywith battery 1 due to the high current drain. This voltage change is not sufficiently large to adversely affect such system components as the relays. However, it is desirable that the filament voltages of the tubes be maintained substantially constant to assure uniformity of operation of the acoustic gear. The filament Voltage is obtained in a circuit paralleling the relay 5K including in series the resistors R64, R65, R63 and R45 connected between Z- and ground and therefore changes in value with changes in the Voltage of battery 2 for the series and parallel battery connections. This change, however, is largely odset or compensated by means of the relay HV which is energized between ground and the negative side of the battery 2 when the batteries are in series (the position in which the control switch CS is rotated clockwise to bridge 2- and Lk) in a circuit beginning at ground and extending through the contacts F2 to the coil of the HV relay. From the coil thereof the circuit continues to the contacts 1+ of the control switch now joined to 2- and terminates at the negative side of battery 2. The contacts HV1 when closed short the resistor R64 and increase the voltage drop across the lilament circuit to provide a voltage` drop thereacross corresponding to that existing when the batteries are in parallel.

Prior to launching of the torpedo, the variable enabler is adjusted to provide the desired distance setting at which enabling occurs. Details of the variable enabler herein disclosed may be found in the copending application of T. A. Daly and H. A. Gill, Serial No. 711,418, filed November V2.1, 1946, entitled Variable Enabler, now Patent No. 2,615,416, and assigned to the same assignee as this invention. Briefly, there are two ways of setting the variable enabler. One method includes a hand adjustment by means of the dial 20 which is loc ated on the variable enabler within the torpedo body. Access to this dial Vis obtained by opening a small port in the torpedo hull. When the dial 20V is rotated, the gears of the drive involving the centrifugal clutch drive the timer 2T in a direction to set any desired time or distance not less than 500 yards into the contacts 2T1 and 2T2 of the timer. Contacts 2T2 do not open until the setting is in excess vof 410 yards. For manual settings the safety feature is a mechanical stop at 500 yards. For electrical settings the safety feature is had in the contacts 2T2 which remain closed until the 410 yard setting is exceeded and provide the .safety cutout in the anti-circling run circuit. Details of the construction may be obtained from the above-mentioned copending application of T. A. Daly and H. A. Gill. The contacts 2T1 and 2T2 with this setting of the dial 20 are open. These contacts may be driven by suitable cams having coniigurations for effecting closing thereof in the desired sequence. In the instant case, the contacts 2T2 close -ahead of the contacts 2T1 for the enabling range which may be set into the timer. The purpose for this will become apparent in a discussion hereinafter given concerning the anti-circling run control ACR.

The variable enabler may also be adjusted by means of an electrical follow-up control, including `a control unit 21 provided with a hand operated dial 22. This control unit is .located within the submarine and by a suitable cable connection with the torpedo in the launching tube controls the motor M3 which by its connection through .the reduction gearing of the centrifugal clutch assembly also operates the timer 2T. The electrical connections for this circuit involve a simple bridge circuit of which the potentiometer P11) forms a pair of adjacent legs, the resistance of each of which depends on the position of the Variable tap driven by the motor M3. The dial 22 drives a similar potentiometer tap on a potentiometer forming the remaining two adjacent legs of the bridge circuit. The particular system, herein employed, is A.C. operated and depends upon instantaneous reversals of phase of the bridge output voltage to the bridge input voltage to obtain reversing control of the motor M3. Thus by either of the methods herein disclosed, the variable enabler may be set to provide the desired enabling distance. The follow-up control, however, provides a means for making last minute corrections in the setting of the enabling distance to vary the enabling of the torpedo in correspondence with last minute changes required by the scene of activity.

The timer 1T may be driven by a simple clockwork mechanism. Itis provided with the three sets of contacts 1T1 and 1T2 which are normally closed and 1T3 which is the normally open set. The contacts 1T1 are the last contacts to operate on the timer. When these contacts open, the energizing circuit for the auxiliary start relay AS is opened and the power supply to the system is removed. The contacts 1T2 and 1T3 may operate together. The contacts 1T2 open the circuit for the motor switch MS and remove power from the propulsion motor circuit. The contacts 1TB upon closing complete the energizing circuit for relay ST and its contact ST3 energizes the ring cap circuit of the carbon dioxide flask. At this time, the contents of the flask are discharged into the ballast chamber of the torpedo and the liquid ballast is ejected to cause the torpedo to surface.

This invention will probably be better understood upon a consideration of the function of the control system for an exercise run which proceeds without incident. Prior .to launching the torpedo, the control switch CS is positioned to connect the batteries 1 and.2 in either series or parallel circuit relation with the propulsion motors. The

Variable enabler is then adjusted to provide the desired enabling distance and, clet it be assumed for the purpose vof this discussion that the enabling distance will be less than the distance afforded by the setting of the contacts of the timer 1T. With this setting of the variable enabler timer, the contacts 2T1 and 2T2 are open. At the instant of launching of the torpedo, the trigger switch TS is closed. This completes an energizing circuit for the detonating cap of the 'gyroscope which may be traced from junction J1 at the positive side of battery 2 to the terminal J2. The circuit continues through the now closed contacts of the trigger switch through the gyro cap GC to the terminal J 4 and the negative side of battery 2. This ignites the powder charge of the starting cartridge for the gyroscope and, in the matter of a fraction of a second, the gyroscope Wheel is accelerated to full operating speed. Closure of the trigger switch TS also establishes an energizing circuit for the auxiliary start relay AS. This circuit proceeds through the trigger switch to the junction I3, through the contacts E1 and 1T1 to the coil of the auxiliary start relay AS and the negative side of battery 2. The auxiliary start relay thus closes substantially instantaneously with closure of the trigger switch and its contacts AS1 connect the positive side of battery 2 to the positive conductor PC. When the positive conductor PC is energized a circuit is completed from terminal I5 to terminal J6 and extends through the normally closed timer contacts 1T2 and the normally closed stop relay contacts ST2 to the normally closed contacts DCO2 of the depth cutout DCO. From this point, the circuit continues through the coil of the motor switch MS to the negative side of battery 2. This energizes the motor switch which closes its contacts M81 and connects the propulsion motors to the batteries 1 and 2. Thus the torpedo is operating under its own power substantially at the instant that it leaves the torpedo tube. At the same time, the timer 1T begins to operate. This timer is normally locked against operation by means of a small electromagnetically operated clutch (the coil alone being shown), generally designated ITC. This clutch contains a small coil and the coil thereof is now energized in a circuit from the positive conductor PC to the negative terminal of battery 2 including the junction points JS and J 6. The timer is released for operation.

The gyroscope G is mounted in the torpedo so that it has three axes of freedom. Therefore, the 4gyroscope tends to maintain a fixed position directionally in space. The gyroscope is equipped with a small arm having a roller mounted at its extremity which operates or rolls along an arcuate segment forming a compass relay GCR. This arcuate segment is `formed in two halves, one of which is of conducting material and the other of which is of electrical insulating material. Normally the gyroscope is aligned by a caging mechanism which is released when the gyroscope rotor has accelerated to full speed so that the gyroscope spin axis parallels the longitudinal axis of the torpedo. If it is desired to have the torpedo proceed on a direct course indicated by the direction in which the launching tube is pointed, the arcuate segment of the gyro compass relay is positioned so that the dividing line between the conducting and non-conducting segments thereof is at the point of tangency of the roller and the arcuate segment. If it is desired to have the torpedo complete a partial circle to either port or starboard after launching, the arcuate conducting segment may -be shifted by suitable means (not shown) relatively to the gyroscope so that the roller lies completely on the conducting portion or the non-conducting portion of the arcuate segment.

The contacts of the gyro compass relay control the relay S, this relay is energized in a circuit from the positive conductor PC including the junctions .l5 and J6, the coil of the relay S and a resistor R30 to the negative side of the battery 2. 'Ihe coil of the relay S is paralleled by the contacts ofthe gyro compass relay. Hence when the roller of this relay is on the conducting portion of the arcuate segment, the coil of the relay S is shunted from the energizing circuit and, when the roller is on the nonconducting portion of the arcuate segment, the shunt circuit is opened and the coil of the relay S is energized.

The relay S is provided with a single set of contacts S1 which are connected in series with the coil of the horizontal gate relay HG. Prior to enabling the torpedo, the contacts HG3 of the horizontal gate relay control the energization of the auxiliary rudder relay AR which in turn, by means of its contacts ARI and ARZ, respectively, control the energization of the starboard and port solenoids SS and PS, respectively. The coil of the auxiliary rudder relay AR is connected in a circuit extending from the positive conductor at junction J5 through the contacts ENZ of the enabler relay EN through the contacts HGB of the horizontal gate relay to the coil of the auxiliary rudder relay and the negative conductor NC. Thus for the specific circuit shown if the torpedo were oi course to the starboard, the roller operated by the gyro would be in a position engaging the conducting portion of the arcuate segment. As a consequence, the relay S is deenergized by the shunt circuit of the gyro compass relay and the relay HG is in its deenergized position shown in the drawing. Since the contacts HG3 are open, there is no circuit for the coil of the auxiliary rudder relay and this relay remains in the deenergized position shown With its contacts ARZ closed. This completes an energizing circuit between the positive and negative conductors between junction points J7 and J8 and operates the port solenoid to apply port rudder. As the torpedo swings back through its neutral position, the roller actuated by the gyro runs otT the conducting portion of the arcuate segment opening the circuit shunting the relay S. As a consequence, the relay S is energized and closes its contacts S1, picking up the horizontal gate relay HG which closes its contacts HG3 to energize the coil of the auxiliary rudder relay. Closure of the contacts AR1 thereof energizes the starboard solenoid SS to apply starboard rudder and swing the torpedo towards the starboard. It will be apparent that the control afforded by the system is hardover-tohardover, and that the path of the torpedo will be approximately sinusoidal about the direct course which the torpedo is taking.

At ythe same time that the steering control for the torpedo is energized, the depth control for the torpedo is energized in a circuit extending from the positive control conductor at junction I7 through the closed contacts EN4 of the enabling relay to the depth control DC involving the phase advance control tor the depth rudders. This control will be described in detail hereinafter but, for the present, it will suffice to state that the control openates to cause the torpedo to dive after leaving the torpedo tube to the predetermined operating depth which may be of the order of 80 feet and to maintain this depth until con-trol by -the acoustic gear is taken over, Thus the torpedo proceeds at its proper operating depth and along the selected course towards the target entirely under the inuence of the gyro and the depth control.

With the closure of the trigger switch and operation of the auxiliary start relay AS, the lament relay F is energized. This relay closes its contacts F1 and F2, the contacts F2 grounding the positive side of the battery 2 and the contacts F1 completing an energizing circuit through the resistors R63 and R45 for the relay 5K and, at the same time, connecting the terminal B16 to the ground. Terminal B10, it lwill be recalled, is connected to the tap on the potentiometer P3 of the horizontal channel detector and lter circuit, and to the terminal B16 of the detector and filter circuit of the vertical -channel placing ground potential at theese two points. The energizing circuit for the relay 5K extends from the positive side of the battery 2 through contacts F1, the resistors R63 and R45 through the coil of the relay 5K, and resistors R65 and R64 to the negative side of battery 2. Relay 5K closes its contacts 5K1 through 5K4 connecting the horizontal and vertical bias batteries HB and VB, respectively, in the horizontal and vertical acoustic channels `and applying the plate and cathode potentials to the direct current ampliiier in both channels in the manner hereinbefore described. The heater circuits for the tubes are connected in parallel with the energizing circuit of the relay 5K. These circuits have not been detailed since it is felt that their connection is well understood. As a result of the operation of the relay 5K and the lament relay F, the acoustic system is placed in operating condition. However, it is prevented from inliuencing the operation of the torpedo prior to enabling because of open circuits through contacts of the enabling relay.

When the torpedo has traveled the distance necessary for the contacts 2T1 of the variable enabler timer 2T to close .an energizing circuit for the coil of the auxiliary enabler relay AEN is completed. This circuit begins at the junction I9 on the positive conductor and extends through the coil of the auxiliary enabler relay through the contacts ZTI of the variable enabler timer to junction 510 and connects with the negative side of the battery at the junction 111. Closure of the contacts AENI completes an energizing circuit from the junction J 12 of the positive conductor for the coil of the enabler relay EN. This circuit is completed through the junctions 110 and 111 (to the negative side of the battery. At this time, the enabler relay closes its contacts EN1 and ENS while opening its contacts ENZ and EN4 which had maintained the torpedo directly under the iniluence of the gyro and depth control. Upon closure of the contacts ENI, the circuit for energizing the auxiliary rudder relay is transferred from the contacts HG3 of the horizontal gate relay to the contacts 3K1 of the relay 3K which is controlled by the output of the direct current amplier of the horizontal channel. In a similar manner, the operation of the depth control of the torpedo, is now controlled in part by contacts 4K1 of the relay 4K. Relay 4K, it will be remembered, is energized normally by the output of the direct current amplifier DCA in the absence of a suiciently strong dilferential signal in the vertical acoustic channel.

Thus let it be assumed for the moment that the torpedo has not yet entered a sound field sufiiciently strong to overcome the normal bias of the vertical acoustic channel. Under this condition, the relay 4K will remain energized and its contacts 4K1 will be closed, to apply energy to the depth control system in a manner similar to that applied through the contacts EN4. As previously described, the torpedo will therefore proceed at the assumed depth of feet.

Returning now to the control of the horizontal channel aiforded by the gyroscope G, the relay S yet continues to control the horizontal gate relay HG. As a consequence, the relay HG is alternately opening and closing its contacts HG1 and HG2. These contacts are respectively connected with the terminals B17 and B13 of the bridge circuit of the horizontal acoustic channel, and with ground through the presently closed contacts VGZ of the vertical gate relay VG, this circuit is traceable to the terminal B10 and ground through the filament relay contacts F2, As a result of the operation of the horizontal gate relay under the influence of gyroscope control, the contacts HG1 alternately ground the opposite sides of the bridge circuit of the horizontal channel. As will be recalled in connection with the discussion concerning the effect of unbalancing the Ibridge circuit by the potentiometer P3, grounding of the terminal B13 causes the terminal A1 (ground) to become positive with respect to Y and therefore the grid of V6 becomes more negative with respect to ground. The consequent reduction of plate current of tube V6 causes tube V7 to conduct and the relay 3K is energized. Conversely grounding of the terminal B17 by the contacts HG1 causes the grid of V6 to become more positive with respect to ground and the resulting increase in plate current ow cuts otf the tube V7 and the relay 3K is deenergized. Following this sequence through the control afforded by the gyroscope should the torpedo be off course to the starboard, the relay S :is deenergized and as a result the HG relay is deenergized and its contacts HG1 are closed. This grounds the terminal B17 and for the assumed condition of opera-tion, the tube V7 is not conducting. Relay 3K is therefore deenergized and its contacts3K1 are open. Since contacts 3K1 are open, the energizing circuit -for the auxiliary rudder relay are open and the contacts AR2 thereo-f are closed. This completes the energizing circuit for the port Solenoid PS `applying port rudder and causing the torpedo to swing back on course again. As the torpedo overshoots its own course position, a port heading thereof results. The roller actuated by the gyroscope moves over the non-conducting segment of the gyrocompass relay. Relay S picks up and energizes horizontal gate relay HG. This closes the contacts HG2 of the horizontal gate relay and grounds the terminal B13. rThe gr-id `of tube V6 therefore becomes more negative and the resulting decrease in plate current causes the plate voltage thereof to rise and the tube V7 passes current. Energizing relay 3K through its contacts 3K1 energizes the auxiliary rudder relay and applies starboard rudder through energization of the starboard solenoid by the contacts ARI. The torpedo again follows the roughly sinusoidal path it had pursued prior to enabling and the influence of gyroscope control remains until the torpedo is completely enabled for acoustic operation.

Assuming now that the torpedo is entering a sound eld along a secant of the sound field circle such that the signal of the starboard -solenoid predominates and that the differential signal resulting from this condition is suicient to overcome the biasing effect on the detector circuit produced by the horizontal gate relay under the inuence of the gyroscope, the predominating current iiow of the starboard signal from terminal Y to H6 biases the tube V6 more negatively and, as a consequence, the tube V7 conducts and the relay 3K is energized to apply starboard rudder and steer the torpedo in the direction of va target signal. As the torpedo swings towards the target, the differential between the starboard signal and the port signal decreases to 4a point where the gyro biasing action overrides the differential signal. The control afforded 'by the gyroscope therefore tends to steer the torpedo along the gyro course. Again the starboard signal will predominate to apply starboard rudder and swing the torpedo back towards the target. As a consequence, the Iaverage course of the torpedo will be along a circular path directed towards the target.

Since the torpedo is operating at a depth considerably below any signal which is being transmitted through the water, the upper hydrophone signal will be stronger than the lower hydrophone signal. As the torpedo approaches the target, the signal differential will steadily increase due to the increasing angle of elevation of the target with respect to the hydrophones. Eventually a point will be reached at which the upper hydrophone signal will be sufficiently strong to produce a differential signal in excess of the normal bias existing in the Ibridge circuit of the Vertical channel. The differential signal resulting from the predominating up signal and being caused by current flow from U16 to point Y in the vertical bridge circuit drives the grid of the tube V14 more positive. The resulting increase in plate current of V14 and accompanying plate potential drop cuts oi the tube V15 and the relay 4K is deenergized to deenergize the phase advance depth control. When the phase advance depth control is deenergized, the energizing circuits for the auxiliary elevator relay AE are open and the contacts AE1 .thereof `are closed. This energizes the up solenoid in a circuit branch paralleling the port and starboard solenoids between the positive and negative conductors and causes the torpedo to rise to attack to the target. As the nose of the torpedo points upwardly towards the target under he influence of the up rudder control, the signal `differential drops 4and the normal bias in the bridge circuit of the vertical channel predomnates causing an output of the direct current amplifier which energizes the relay 4K. Again the phase advance depth control takes over tending to nose the torpedo down and when the up signal again predominates suiiciently the cycle is repeated. As the torpedo approaches .the target more closely, the signal diiferential increases in magnitude and eventually a point is reached wherein the required level of signal differential is maintained for a sucient period of time that complete transfer to acoustic control may be effected.

This complete transfer to :acoustic control is effected through the control of relay AG, the auxiliary gate relay, by the relay 4K. The auxiliary gate relay forms part of a time delay control which includes the control tube 2CT which is of the gas-iilled type. The cathode of this tube in connected to ground in a circuit including junction 114, 515 and the contacts F1 and F2 of the filament relay. The plate of the control tube 2CT is connected to the positive lterminal of the battery 6 in a circuit including the coil of horizontal gate lockup relay HGL and the contacts 5K3 of the relay 5K. The tiring anode of the tube 2CT is connected to ground through the normally closed contacts AG2 of the auxiliary gate relay and the resistor R31 which connects with the junction 114. A capacitor C12 -is connected between the cathode and the firing anode of this tube and as a consequence is shortcircuited when the contacts AG2 are closed- When the relay AG is energized by the relay 4K, its contacts AG1 connect the capacitor C12 in series with a resistor R32 between ground and the positive side of the battery 6 to cause capacitor C12 to charge. The charging rate of capacitor C12 is determined by the ohmic value of the .resistor R32 and is selected to provide the desired time interval before the capacitor voltage exceeds the breakdown voltage of the tube that a sound field of sufcient intensity may be had for adequately controlling the torpedo.

Assuming now that the relay 4K is deenergized due to a predominating up rudder signal, the relay AG is energized and its contacts AG1 are closed initiating charging of capacitor C12. If the torpedo is sufficiently close to the target so that the differential signal of required magnitude is maintained for the time interval required for the capacitor voltage -to break down the control tube, the tube tires and thereafter operates independently of the auxiliary gate relay and a circuit therethrough for energizing the horizontal gate lockup relay HGL is completed. This circuit extends from the positive side of the battery 6 and the contacts 5K3 through the horizontal gate lockup relay coil and the tube 2CT to the junction 114 which is connected to ground through the contacts of the filament relay. Energization of the horizontal gate lockup relay causes the contacts HGL1 thereof to close and completes an energizing circuit for the coil of the vertical gate relay VG which includes the auxiliary enabler contacts AENl, the contacts HGL1 and the coil of the vertical gate relay. The contacts VG2 of the vertical gate relay now open Land the contacts VG1 thereof close. This disconnects from ground the contacts HG1 and HG2 of the horizontal gate relay which lformerly biased the bridge circuit of the horizontal channel and connects the terminal B8 which is a center tap of the resistor combination R91 and R92 -straddling the input terminals of the bridge circuit, to ground. Thus the bridge is restored to electrical equilibrium and the influence of the gyro biasing potentional is removed completely. As a consequence, the torpedo now follows a course determined entirely by the differential signal 19 of the horizontal channel. The average course is always directed Vat the signal source or target.

Neglecting for the moment the function of the broach cutout if for some reason the torpedo should miss the target on its first pass, the signal differential in the vertical channel will be insuflicient to maintain the relay 4K deenergized and keep up elevator on the torpedo. Relay 4K will therefore be energized and the phase advance depth control will be effective to cause the torpedo to dive. After proceeding beyond the target, the torpedo will tend to turn either to the port `or to the starboard depending upon which hydrophone in the horizontal channel is receiving the stronger signal. As the torpedo circles and dives to come back to the attack, the up signal will again predominate sufficiently to deenergize the relay 4K and remove the effect of the depth control. Up rudder is again applied and, at the same time, the torpedo orients itself directionally to renew its attack upon the target or signal source. This action will continue until such time as contact with the target is made and in the war shot torpedo the inertia switch detonates the warhead. In the exercise shot torpedo the broach cutout initiates blowing of the ballast and stopping of the propulsion motors.

In the test -torpedo should the torpedo broach the broach cutout contacts BCO1, which open when the torpedo submerges, will close. Closure of the contacts BCOl establishes an energizing circuit for the coil of the stop relay ST. This circuit extends from the positive conductor at the junction 112 through the contacts AENI of the auxiliary enabler relay through the broach cutout contacts BCOl and the coil of the stop relay to junction 116 which connects with the negative terminal of the battery 2. The stop relay picks up and closes its contacts ST4 which maintains an energizing circuit for the coil of the electromagnetic clutch ITC of the timer 1T. The contacts ST3 close and complete an energizing circuit for the firing cap of the carbon dioxide flask CO2. The discharge of the cartridge which follows opens the valve of the carbon dioxide flask permitting the contents of the flask to exhaust into the ballast chamber Of the torpedo ejecting the ballast fluid and rendering the torpedo buoyant. The contacts ST2 open and deenergize the coil of the motor switch MS. MS now drops out and deenergizes the propulsion motor circuit. When the time setting of the timer 1T has expired, the contacts 1T1 open and open the energizing circuit for the auxiliary start relay AS. This opens the auxiliary start relay contacts AS1 and disconnects the positive conductor PC from the positive side of the battery 2. As a consequence, all of the control elements of the system are deenergized.

If during the course of its operation the torpedo had proceeded to a depth beyond safe limits, the contacts of the depth cutout would have been actuated, contacts DCOZ opening and contacts DCO1 closing. Opening of the contacts DCO2 disconnects the coil of the motor switch and deenergizes the propulsion motor. While closure of the contacts DCO1 res the cartridge of the carbon dioxide flask to render the torpedo buoyant. This circuit includes the contacts of the auxiliary enabler relay, the broach cutout contacts BCO1, the contacts DCO1 of the depth cutout which are now presumed to be closed and the contacts ST1 of the stop relay through the firing cap of the CO2 ask to the negative side of the battery 2.

The phase advance features of the depth control unit are covered in detail in a copending application of H. L. Prescott, Serial No. 653,188, filed March 8, 1946, entitled Control System, and assigned to the same assignee as this invention. In the conventional type of depth control, a pendulum closes the contact to operate the elevator solenoids as soon as the pitch angle of the torpedo passes the neutral position. The delays in operation of the relays, torpedo inertia and other mechanical components cause the torpedo to proceed a considerable distance away from the neutral position before the elevators are actually thrown, thus causing wide variations in pitch angle during the running of the torpedo. The function of the phase angle advance control circuit is to anticipate this departure from course and to apply the elevator control in advance of that which would result from the conventional use of the pendulum. This is accomplished essentially by reversing the usual action of the control circuits so that the up rudder is controlled by the pendulum contact which closes when the nose is up and the down rudder is controlled by the contact which closes when the nose is down, and both rudders are operated by the opening rather than the closing of their respective pendulum contacts. In addition, a bias is applied to the pendulum by a source which is a function of water pressure and, therefore, an indication of the depth at which the torpedo is operated. In the drawing, this is accomplished by means of a hydrostat HS which may be a simple bellows or diaphragm which is exposed to water pressure and which is connected mechanically with the arm of the pendulum. Thus if the torpedo is operating too deep or too shallow, a corresponding bias on the pendulum is produced to correct the operating condition.

When the torpedo is fired, the forces of acceleration acting on the pendulum P close the high contacts which are designated P2 in the drawing. Closure of these contacts prior to enabling of the torpedo establishes an energizing circuit from the positive conductor at junction J7 through the contacts EN4 and the pendulum arm to the coil of the auxiliary down relay AD to the negative conductor NC. Relay AD picks up opening its contacts AD1 and closing its contacts AD2. This completes an energizing circuit from the positive conductor at junction 117 through the closed contacts AD2 and the coil of the auxiliary elevator Irelay AE to the negative conductor NC. The auxiliary elevator relay picks up and closes its contacts AEZ while opening its contacts AE1. The up rudder solenoid US is deenergized and the down rudder solenoid DS is energized applying down rudder. The torpedo, therefore, immediately starts down upon firing. As soon as the torpedo leaves the tube and' the acceleration is over, the normal operation of the depth control then continues. The force exerted on the pendulum by the hydrostat HS during the initial diving period is suicient to maintain down rudder within a given limit of pitch angles. Thus the torpedo is prevented from diving at too steep an angle and thereby possibly overshooting by a considerable margin the selected depth of operation.

Assuming now that the torpedo is operating at the selected depth and that the nose is headed down, the contacts P1 close. This energizes the auxiliary up relay AU closing its contacts AUI and opening its contacts AU2. This completes an energizing circuit for the sequence control relay SC which extends from the junction J 7 through the contacts EN4 through the closed contacts AUI, the coil of the sequence control relay SC and the contacts AD1 which are now closed to the negative conductor. The sequence control relay closes its contacts SC1 and SC2. Contacts SC1 parallel the contacts AUl and maintain the sequence relay energized independently of the auxiliary up relay. Contacts SC2 complete a partial energizing circuit for the coil of the auxiliary elevator relay but this circuit is presently broken in the contacts AU2 which are now open. Under these conditions, the up solenoid is energized and up rudder is applied to the torpedo tending to cause the torpedo to reverse its angular movement and to swing to an up-nose position. As the longitudinal axis of the torpedo swings through its neutral position, the contacts P1 of the pendulum open and deenergize the auxiliary up relay. The contacts AUZ now close and the auxiliary elevator relay is energized in a circuit between the positive and negative conductors including the closed contactors SC2 and AUZ. Thus while the torpedo is swinging about its pitch axis to up-nose position, the contacts AEZ are closed to apply down elevator. Due to the inertia of the torpedo, however, the torpedo continues to swing nose up a short interval of time after the down elevator is applied. Meanwhile, in the nose-up position, the contacts P2 of the pendulum close and energize the auxiliary down relay. The contacts AD2 maintain the coil of the auxiliary elevator relay energized. With a continued application of down rudders, the torpedo is accelerated angularly in a nose-down direction and eventually again reaches its neutral position wherein the contacts P2 open and the contacts P1 close. This causes the control cycle in the vertical plane to be repeated.

As previously mentioned, after enabling, the contacts ENS are closed. During periods when the sound eld sensed by the vertical acoustic channel is insucient to deenergize the relay 4K, the energizing circuit for the phase advance depth control is maintained through the contacts EN3 and 4K1. However, when the relay 4K is deenergized due to the influence of a strong differential signal in the vertical channel indicating that a target lies above and in proximity of the torpedo, the relay 4K is deenergized. Thus the contacts 4K1 are open and the energizing circuit for the phase advance depth control is interrupted. Under this circumstance, it will be apparent that the auxiliary elevator relay will remain in its deenergized position with its contacts AE1 closed and the up solenoid energized to apply up rudder causing the torpedo to rise to attack the target.

The control afforded by the anti-circular run control in conjunction with the variable enabler, it will be recalled, protects the launching craft from attack by the torpedo should the torpedo be prematurely enabled after launching. In a manner similar to the switch over control of the torpedo to the acoustic gear, the anti-circling run circuit employs a gas tube 1CT which functions `as the trigger in the control system. The cathode of this tube is connected to the negative side of the battery 2. While the plate of this tube is connected through the coil of the relay 'E and contacts A1 of the relay to the positive side of a battery '7 which is connected through the trigger 'switch TS in series with the battery 2. A parallel branch of this circuit extends through the contacts B3 of the relay B. A capacitor C13 is connected between the cathode and the firing anode of the control tube 1CT and the charging of this capacitor is had in one instance by operation of the relays C and D which respectively parallel the starboard and port solenoids, and in yanother instance by the contacts B2 and either of lthe parallel connected contacts A2 and 2T2. In the first instance, resistor R9 is connected by contacts of the relays C vand D in an energizing circuit to charge the capacitor at a given rate. In the second instance, a resistor R11 of sufficiently low ohmic resistance provides rapid charging of the capacitor to cause a `quick breakdown of the tube. The purpose of this arrangement will better be understood by considering the function of this system for yan assumed operating condition.

Let it be assumed lthat through inadvertence, the torpedo is enabled for acoustic steering at the time of firing. For this condition, the variable enabling timer 2T Would have been improperly set and the contacts 2T1 thereof and 2T2 would be closed at the time of tiring. As a consequence, an energizing circuit for the auxiliary enabling relay is established through the timer contacts 2T1 including the junction points I9, l1()v and 111 for the complete energizing circuit. Operation o-f the auxiliary enabler relay energizes the coil of the enabler relay EN and this relay operates to` establish the switchover circuits to yacoustic control. Since the torpedo would be operating in the sound field of the launching craft, the acoustic iield would be sufficiently intense to provide a complete transfer to acoustic control by reason of the control effect of the relay 4K responsive to the Vertical acoustic signal on the tube ZCT. Thus the tendency of the torpedo under complete `acoustic control would be to circle and attack the launching craft. Under these conditions, the energizing circuit for the relay A is completed through the auxiliary enabler contacts AENL Thus the contacts A2 of this relay -are closed. It will be noted that the contacts 2T2 of the variable enabler timer parallel the contacts A2 of the relay A. This affords a margin of safety in the event of failure of either set of the mentioned contacts. The contacts A2 and 2T2 cooperate with contacts of the relay B. Relay B, in turn, is energized by closure of the contacts TD1 of the relay TD. Each of these relays responds to energization of the propulsion motor circuit and thus do not operate until the motor switch MS has closed. Relay TD is a time delay relay `and the control of the relay B yafforded thereby is such as to provide approximately 5 seconds delay in the present case before the relay B closes. When relay B closes, its contacts B1 provide a holding circuit for the coil thereof which is independent of the contacts TD1 of the time delay relay. For the Iassumed conditions, however, the relay B due to the time delay in operation provides a circuit through the contacts B2 thereof in conjunction with the now closed contacts A2 and ZTZ for the capacitor C13. This circuit extends from the battery 7, which it will be recalled is connected in series with the main battery 2 and which passes through the contacts A2 or 2T2 throughV the contacts B2 and resistor R11 to the capacitor C13 where the circuit extends to the negative side of the battery 2. As previously noted, the resistor R11 is of sufliciently low ohrnic value that rapid charging of the capacitor C13 is obtained. This may be so adjusted that a breakdown voltage for the tube 1CT may build up across the capacitor in as little as V10 of a second. Thus the tube tires almost immediately if the torpedo is enabled at the time of launching and upon firing an energizing circuit for the coil the relay E is established. This circuit is traceable from the positive side of the battery 7 through the contacts B3, the coil of relay E, the tube 1CT and thence to the negative side of battery 2. Energization of the relay E causes the contacts E1 thereof to open. Contacts E1 are disposed in series circuit with the coil of the auxiliary start relay AS. Hence this relay is deenergized and its contacts AS1 open to remove power [from the positive conductor PC. Removal of power from the positive conductor deenergizes the control relays and as a consequence the motor switch MS drops out and opens the propulsion motor circuit stopping forward motion. Stopping of the forward motion of the war ,shot torpedo causes that torpedo to sink because of its negative buoyancy and danger to the launching craft is eliminated.

-Another condition which is equally dangerous results from improper operation of the steering solenoids such as sticking of the relays and improper gyro operation. Normally during the interval prior to enabling, the torpedo follows a course controlled by the setting of the gyroscope G and the port and starboard solenoids during this interval will have been alternately operating. 'This alternate operation of the port and starboard solenoids energizes the relays C and D connected in parallel therewith as previously described. -Each time the starboard solenoid is energized, the relay C opens its contacts C2 and closes its contacts C1. This completes an enerlgizing circuit for the capacitor C13 from the battery 7 through the contacts A1, which are now closed, through the resistor R9 and the contacts C1 and D2, now closed, to the capacitor C13 and the negative side of battery 2. The capacitor C13 now charges at a rate depending upon the ohrnic value of the resistor R9. VIhis charging rate is such as to prevent breakdown due to normal operation of either of the port or starboard solenoids. When the starboard solenoid is deenergized, the relay C2 drops out and its contacts C2 close completing a discharge circuit for the capacitor C13 which includes the resistor R10 and the contacts C2 and D2 both of which are now closed. EIn the next instant, the auxiliary rudder relay transfers the energizing `connection to the port solenold and the relay D paralleling this solenoid is energized closing its contacts DI. At this time, the capacitor C1.:` is charged through the circuit including the resistor R9 but in this instance including the contacts DI through the capacitor to the negative side of the battery 2. Thus with each operation of the port and starboard solenoids, the capacitor C13 is charged and in the instant of time in which the lauxiliary rudder relay is transferring the energizing connection for the port and starboard solenoids the capacitor C13 is discharged through the normally closed contacts C2 and D2 of the relays C and D. By proper selection of the time constants of the capacitor charging circuits, it is possible to provide for substantially an infinite number of normal operations of the port and starboard solenoids |before a breakdown voltage across the capacitor C13 is accumulated, yet at the same time affording a suicient rapid rate of charging that breakdown of the tube may obtain at any point on the cycle should the application of the port or starboard solenoid persist beyond a given period of time. Thus if one of the relays controlling energization of the solenoids PS and SS should fail and maintain port or starboard rudder beyond a given interval of time determined by the charging rate of capacitor C13, the capacitor voltage triggers the control tube ICT which then completes the circuits for stopping the torpedo.

The mechanics of the timer 2T `are such that any setting thereof below a minimum distance, say 500 yards, prevents operation of the timing mechanism by the drive thorugh the centrifugal clutch from the propulsion motor. For this reason, the relay A remains in its deenergized position and in conjunction with tiring of the tube ICT completes the energizing circuit for the relay E which opens its contacts EI to drop out the auxiliary start relay and at the same time closes its contacts E2 to provide a holding circuit therefor which is independent of the position of the contact A. As a result, the motor switch is deenergized and the torpedo stops. Similarly, the electrical control is so constructed that enabling settings at ranges less than 500 yards are not obtainable. This is accomplished by the provision of a stop on the panel for dial 22 `of the electrical follow-up control, which stop is so placed that the potentiometer operated by dial 22 introduces a [bridge unbalance into the system corresponding to a 500 yard setting on the variable enabler.

Assuming now that the enabler has been set for a distance beyond the assumed 500 yard minimum, the function thereof will be in a normal manner to close the contacts ZTZ rwhich may be set for 410 yards and then to close the contacts ZTI which energize the auxiliary enabler relay AEN, in turn, bringing in the enabler relay EN and initiating the control `for transfer to acoustic steering. Under these conditions, the capacitor C13 will have been charging at a normal charging rate depending upon the function of the port and starboard solenoids and, at the time of energzation of relay A which opens the contacts A1, will not have built up a suicient charging voltage to cause breakdown of the control tube ICT. The anti-circular run control is, therefore, disabled and the torpedo proceeds under the influence of the `gyro- Scope and depth control until the intended sound field becomes sufficiently strong to effect complete switchover to acoustic steering.

IIn lgeneral, to keep the torpedo from ever returning to the craft, it is necessary to restrict the maximum turn to 180 or less. For an electrical control gyroscope using 180 arcuate contact segments in the gyro compass relay, the same limit is imposed by the fact that in a circling run `due to a mechanically jammed rudder the solenoids are energized alternately for 180 of turn. On the other hand, in order to allow angle shots, the largest gyro angle to be permitted will determine the time constant of the resistor capacitor charging and discharging circuits.

The schematic diagram for the war shot torpedo is shown in FIG. 3. The lwar shot torpedo, unlike the exercise shot, is not intended to =be recovered. Hence, it is built for but a single shot. 'For this reason, all of the control elements of the test torpedo which provide for the recovery thereof may be eliminated from the War shot circuits. Such circuit elements include the depth cutout, the broach cutout, the timer IT, the stop relay and the carbon dioxide ask which exhausts the liquid ballast, the torpex loaded war head being substituted for the ballast chamber in the war shot torpedo. t

The motor switch is now energized in a circuit from the positive conductor PC directly to the coil of the motor switch and the negative side of battery 2. The auxiliary start relay AS is now energized in a circuit including only lche contacts EI of the relay E and the trigger switch contacts. Previously this circuit contained the contacts ITI of the timer 1T, the purpose of that element being to stop the torpedo after a predetermined length of exercise run. The remaining system elements and their function in the complete control system is similar to that in the exercise shot torpedo. Hence, the function of the war shot torpedo with the exceptions noted will `be understood from the `description rriade in connection with the preceding figures of the drawing.

An additional element is utilized in the war shot scheme and that is the arming mechanism of FIG. 3a which provides for the detonation of the torpex war head of the war shot torpedo. Details of this yarming mechanism may be had upon reference to the copending application of Walter E. Lewis, Serial No. 662,948, filed April 18 1946, entitled Timing Mechanism, now Patent No. 2,682,223, and assigned to the same assignee as this invention. This circuit is comprised of an inertia switch IS which is connected in series with the contacts AMI of the arming mechanism AM and the battery 8. The farming mechanism comprises Ia squib SQ which in its normal position straddles a set of contacts AMZ, each side of which is at ground potential. A wire filament is connected in the squib to the electrically insulated points of this squib which straddle the mentioned contacts. This wire lamentt is buried in a highly sensitive powder charge which is ignited when the wire filament is charged with electricity tand heated. The squib is carried in a suitable mechanism (no-t shown) which is driven, for example, from a suitable water wheel operated when the torpedo moves through the water so that the squib assembly is moved upward, as viewed, to bridge the contacts AMI connecting the wire lament across these contacts and in series with the battery circuit. This movement of the squib assembly also moves the squib into intimate relationship with the booster charge forming part of a powder train employed to detonate the war head of the torpedo. When the torpedo strikes its target, the inertia switch IS closes due to the high rate of acceleration and the wire filament is connected in the battery circuit igniting the war head.

The foregoing disclosure and the showings made in the drawings are merely illustrative of the principles of this invention and are not to be interpreted in a limiting sense. The only limitations are to be determined from the scope of the appended claims.

We claim as our invention:

1. In a control for a torpedo having an electric drive and automatic tracking means, the combination of, an electrically operated switch for energizing said electric drive, means operated at launching of said torpedo for energizing said electrically operated switch, a distance switch operable after torpedo has traveled a predetermined minimum distance Vfor initiating control of said torpedo by said automatic tracking means, a control tube having a predetermined breakdown voltage, means responsive to the electrical output of said control tube for deenergizing said electrically operated switch, and time delay means operable in conjunction with said distance switch upon premature operation thereof for applying breakdown voltage to said control tube.

2. In a control for a torpedo having an electric drive and automatic tracking means, the combination of, an electrically operated switch for energizing said electric drive, means operated at launching of said torpedo for energizing 4said electrically operated switch, a distance switch for initiating control of said torpedo by said automatic tracking means, a control tube having a predetermined breakdown voltage, a capacitor for applying said breakdown voltage, a source of electrical energy, time delay means operable in conjunction with said distance switch upon premature operation thereof for applying said 4source to said capacitor and producing a suicient voltage thereacross to breakdown said control tube, and means responsive to the electrical output of said control tube for deenergizing said electrically operated switch.

3. In a control for a torpedo having an electric drive and automatic tracking means, the combination of, means for supplying electrical energy, an electrically operated switch for connecting said means for supplying electrical energy with said electric drive, means operated at launching of said torpedo for energizing said electrically operated switch, a distance switch for initiating control of said torpedo by said automatic tracking means, a control tube having a predetermined breakdown voltage, a capacitor for applying breakdown voltage to said control tube, time delay relay means connected with said means for supplying electrical energy by said means operated at launching, said time delay relay operating in conjunction with said distance switch upon premature operation for energizing said capacitor and causing a breakdown voltage to build up thereacross, and means responsive to the electrical output of said control tube for deenergizing said electrically operated switch.

4. In a system of control for a conveyance adapted for operation in a iluid medium, said conveyance having a propulsion means, and having a steering means and an elevating means for controlling the direction of movement of said conveyance in the medium, the combination comprising a gyroscope carried by said conveyance, means responsive to said gyroscope for controlling said steering means, means responsive to the pressure of the uid medium for controlling said elevating means, first acoustic responsive means adapted to control said steering means to direct the conveyance toward a source of acoustic energy in the uid medium when the strength of the acoustic field at the conveyance exceeds a predetermined minimum, second acoustic responsive means adapted to control said elevating means to direct the conveyance toward a source of acoustic energy in the uid medium when the strength of the acoustic iield exceeds a predetermined minimum, which is greater than the strength necessary to operate said rst acoustic responsive means, a distance switch operable after the conveyance has traveled 'a predetermined distance to enable the first acoustic responsive means to override the gyroscopically controlled means to control the steering means when the acoustic eld at the conveyance due to the source of acoustic energy is in excess of a predetermined minimum and the conveyance is not heading toward the source of the field, said switch also enabling the second acoustic responsive means to override said pressure responsive means to control said elevating means when the strength of the acoustic field at the conveyance due to the source of acoustic energy exceeds a predetermined minimum, means responsive to said second acoustic responsive means for disconnecting the gyroscopically controlled means from the steering means when said lsecond acoustic responsive means causes the elevating means to direct the conveyance in an upward direction for longer than a predetermined minimum period of time, and means connected to said distance switch for stopping the propulsion means of the conveyance on premature operation of said distance switch.

5. In a system of control for a conveyance, as defined in claim 4, the combination of means electrically connected to said steering means for stopping the propulsion means of the conveyance if the steering means guides the conveyance in a circle before the distance switch enables the rst and second acoustic responsive means.

6. In a self-guided torpedo having propulsion means and means controlling the direction in which the torpedo travels, said means including a rudder and rudder operating means adapted to put the rudders in either the port or starboard position, an anti-circling-run control circuit comprising a control tube having an anode and a cathode, a capacitor connected between the cathode and the anode, circuit means including said capacitor, direct current supply means, resistance means and switching means, said switching means being actuated by the rudder operating means to complete `said circuit means to charge said capacitor when the rudder is in port or starboard positions,

' said circuit means also including a low resistance means connected across said capacitor and rendered operable to discharge said capacitor by said switching means when said rudder is in its neutral position, and an electrically operated switch in series with the anode of the control tube and adapted to stop the propulsion means of the torpedo when actuated, whereby if the rudder means steers the torpedo in a circular path for a period of time in excess of the period of time it takes the direct current source to build up a potential on said capacitor equal to the breakdown potential of the control tube, the propulsion means is stopped.

References Cited inthe le of this patent UNITED STATES PATENTS 952,451 Leon Mar. 22, 1910 1,121,563 Leon Dec. 15, 1914 1,137,222 Leon Apr. 27, 1915 1,303,044 Dieter May 6, 1919 1,312,510 Baker Aug. 12, 1919 1,344,352 Parmele et al. June 22, 1920 1,346,264 Shelton July 13, 1920 1,378,291 Sperry May 17, 1921 1,500,114 Dieter July 8, 1924 1,588,932 Blair June 15, 1926 1,659,653 Hammond et al Feb. 21, 1928 1,855,422 Roussey Apr. 26, 1932 2,414,928 Chilton Ian. 28, 1947 2,419,173 Smith Apr. 15, 1947 2,991,742 Steinberg July 11, 1961 

